Method of mixing molten pig metal



v (No ModeL) W. R. JONES. METHOD OP MIXING MOLTEN PIG METAL. No.404,414. y BatentedJune 41889.

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W. R. JONES. y METHOD 0F MIXING. MOLTEN PIG METAL. N'o.^404,414.Patented June '4, 1889.

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VILLIAM R. JONES, OF BRADDOOK, PENNSYLVANIA.

METHOD OF MIXING M'OLTEN PIG IVIETAL.

SPECIFICATION forming part of Letter s Patent No. 404,414, dated June 4,1889.

, Application tiled October 31, 1888l Serial No. 289,672. (Nospecimens.)

ing Molten Pig Metal; and I do hereby declare the following to be afull, clear, and exact description thereof.

I shall describe my invention with reference to theaccompanyingdrawings, in Which- Figure 1 is a vertical longitudinalsection of apparatus which I have invented for practicing my invention.Fig. 2 is an end elevation of the mixing-vessel and its actuatingmechanism, viewed in the direction of the arrow A of Fig. 1. Fig. 3 is aplan view of the parts shown in Fig. 2.

Like symbols of reference indicate like parts in each.

The primary object of my invention is to provide means for rendering theproduct of steel-works uniform in chemical composition. In practice itis found that metal tapped from different blast-furnaces is apt to varyconsiderably in chemical composition, particularly in silicon andsulphur, and such lack of uniformity is observable in different portionsof, the same east, and even in different portions of the same pig. Thefollowing table, giving the analyses of metal contained in differentladle-charges tapped from a blast-furnace at a single casting at theEdgar Thomson Steel Vorks, Braddock, Pennsylvania, will illustrate thefact: Ladle No. 1 contained siliconl 4.15 per cent., sulphur .O15 percent.; ladle No.2 contained silicon 4.07 per cent., sulphur No. 3contained silicon 2.89 per cent., sulphur .030 per cent.; ladle No.5contained silicon 1.23 per cent., sulphur .120 per cent.; ladle No. 6contained 'silicon 2.52 per cent., sulphur .O61 per cent.; ladle No. 7contained silicon .6G per cent., sulphur .143 per cent. The consequenceof this tendency of the silicon and sulphur to segregate or form pocketsin the crude metal is that the product of verters or otherwise in likemanner lacks uniformityin these elements, and therefore often causesgreat inconvenience and loss, making it impossible to manufacture allthe articles of a single orderof homogeneous composition.

the refining process in the con-v Especially is this so in the processof refining crude iron taken from the smelting-furnace and chargeddirectly into the converter With-v out remelting in a cupola, and,although suoli direct process possesses many economic advantages, it hason this account been little practiced.

For the purpose of avoiding the practical evils above stated I use inthe refining process a ehargecomposed not merely of metal taken at onetime from the smelting-furnaee, but of a number of parts taken fromdifferent smelting-furnaces, or from the same furnace at differentcasts, or at different periods of the same cast, and subject the metalbefore its final refining to aprocess of mixing, Whereby its particlesare diffused or mingled thoroughly among each other, and the entirecharge is practically homogeneous in composition, representing in eachpart the average of the unequally diffused and segregated elements ofsilicon and sulphur originally contained in each of the several parts orcharges. By proceeding in this Way not only is each charge for therefining furnace or converter homogeneous in itself, but, as itrepresents an average of a variety of ununiform constituent parts, allthe charges of the converter from time to time Will be substantiallyuniform,

and the products of all will be homogeneous.

To this end my invention maybe practiced With a variety of forms ofapparatus-for eX- ample, by merely receiving inv a chargingladle anumber of small portions of metal taken from several ladles orreceiving-vessels containing crude metal obtained at different times orfrom different furnaces, the mixing being performed merely by the act ofpouring into the charging-ladle, and other like means may be employed. Iprefer, however, to employ the apparatus shown in the aecompanyingdrawings, and have made it the subject of a separate patent application,Serial No. 289,673, and, Without intending to limit the invention to theuse of that specific apparatus, I shall describe it particularly, sothat others skilled in the art may intelligently employ the same.

My invention is not limited to its use in connection with converters,since similar advantages may be obtained by casting the IOC metal fromthe mixing-vessel into pigs for use in converters, puddliligfurnaces,.orfor any other uses to which pig-iron may be put in the art.

Referring now to the drawings, 2 represents the reservoir beforementioned. lt consists of a covered hollow vessel having an outer casing3, of iron or steel, which is suitably braced and strengthened byexterior beams and tie-rods, as shown in the drawings. The wholeinterior of the vessel is lined with iire-brick or other refractorylining, which should be of sufficient thickness to retain the heat ofthe molten contents of the vessel and to prevent chilling thereof. Thevessel is strongly braced and supported by braces and tie-rods, and maybe of any convenient size, holding, say, one hundred tons of metal,(more or less,) and its shape is preferably such as shown in'thedrawings, being rectangular, or nearly so,.in cross-section and anirregular trapezium in longitudinal section, one end being considerablydeeper' than the other. At the top of the deeper end, which I call therear end, is a hopper 5, into which the molten metal employed incharging the vessel is poured, and at the front end is a discharge-spout6, which is so located that the bottom of the spout is some distanceabove the bottom of lthe vessel-say two feet in a hundred-ton tank, andmore or less, aceordin g to the capacity of the vessel--the purpose ofwhich is that when the metal is poured out of the spout a considerablequantity may always be left remaining and unpoured, and that wheneverthe vessel is replenished there may already be contained in it a body ofmolten metal with which the fresh addition may mix. I thus secure, asmuch as possible, uniformity in character of the metal which is fed toand discharged from the tank, and cause the fluctuations in quality ofthe successive tappings to be very gradual.

For convenient use of the apparatus I have found it best to so arrangeit that it is adapted to receive its charges of metals from cars orbogics 7, which run on an elevated track at about the level of thenorlnal position of the hopper 5, and to discharge its contents intosimilar cars or bogies 15 on a track below the spout (i. In order tofacilitate the charging and discharging of the metal, the vessel is seton journals or bearings 8, which have their bearings in suitablepedestals 9, and its rear end is provided with depending rack-bars lO,which are pivotally connected with the bottom of the mixing-vessel 2 andare in gear with 'pinions 1l, the shaft of which is connected bygearings 12 with the driving mechanism of a suitable engine. The pinionsare held in gear with the rack-bars by idler wheels or rollers 13. Asthe journals or bearings S are located on a transverse line somewhat inad Vance of the center of gravity of the vessel,

it tends by its own weight to tilt backward into the position shown inFig. 1, but may be restored to a level position by driving the pinions11, and thus raising the rack-bars 10 until the front part of the bottomof the vessel as follows: XVhen the vessel is in the back#-lwardly-inclined position shown in Fig. y1, it is ready to receive acharge of metal from the car 7. Before introducing the first charge,however, the mixing-vessel should be heated by internal combustion ofcoke or gas, and when the walls of the vessel are suiiiciently hot tohold the molten metal without chilling it it is charged repeatedly fromthe cars 7 with metal obtained either from a number of furnaces or atdifferenttimes t'rom a single furnace. The charges of metal introducedat different times into the vessel, though diftering in quality, mixtogether, and when the vessel has received a sulii cient charge itscontents constitute a homogeneous molten mass, whosevquality may not beprecisely the same as that of any one of its constituent charges, butrepresents the average quality of all the charges. If desired, thecommingling of the contents maybe aided by agitation of the vessel onits tru unions, so as to cause the stirring or shaking of its liquidcontents. The mixing-cl1amber being deeper at its rear than at the frontend, as before described, and its normal position when not dischargingmetal for the purpose of casting being with the bottom inclined upwardtoward the front or discharging end, and the bottom et' the spout beingsituate above the bottom of the vessel at its forward end, it is adaptedto receive and hold a large quantity oi' molten met-al without itssurface rising high enough to enter the discharge-spout.

The discharge-spout G is furnished with a movable cover operated by aweighted lever 16, which, when closed, serves to exclude the outside airand prevent a draft of air through the vessel and the consequent rapidcooling of the molten contents. lf care is exercised in lkeeping thecover closed, the metal can be kept in a fluid condition for a longtime, the heat being kept up by repeated fresh charges of molten metal,and, if necessary or found desirable, by burning gas introdllced by apipe or pipes into its interior.

After the vessel is properly charged, the metal is drawn oit' into thecars 15 from time to time, as it is needed, by opening the door or cover1G of the spoilt G and driving the en gine 12, so as to elevate the rearend of the vessel and tilt it forward, and thus to discharge anyrequired amount of its contents in the manner before explained into thecars 15, which are transported to the converters, or the metal is castinto pigs or otherwise used. The tilting of the Vessel docs not,however, drain ofl all the contents thereof, a portion being preventedfrom escaping by reason of the elevated position of the spout (i, and asthe vessel is replenished from time to time each new charge mixes withparts of previous charges remaining in the vessel, by which TOO IIO

means any sudden variations Vin the quality of the metal supplied to theconverter is avoided. Instead of discharging the metal into the cars 12and carrying it in the cars to the converters or casting-house, thevessel 2 may be so sit-nate relatively to the other part-s of afurnace-plant as to deliver its contents immediately to the convertersor other place Where it is to be utilized.

I iind it in practice very advantageous to employ tWo or moremixing-vessels constructed substantially as I have described, and todraw a portion of each converter-charge from each of the mixing-vessels.My invention is, however, not limited to the employment of two or anyspeciiic number of such vessels.

I shall nonr describe, briefly, other parts of the apparatus Which aredesirable and important'in its practical use.

At the top of the vessel 2 are man-holes 17, designed to permit ofaccess to its interior for the purpose of repairingor fixing the lining.These holes are provided with suitable covers 18 to exclude cold draftsof air from .entering the interior. There is also a hole 19 at the rearend of the vessel nearthe top, through which a rabble may be insertedfor the purpose of assisting or accelerating the mixing of the moltenmetal, and at the other end, at the level of the bottom of the interior,there are holes 20, provided with suitable spouts to enable all themolten contents to be drawn off when itbecomes necessary to do so. (SeeFig. 3.)' The holes 2O should be provided with suitable Stoppers.

I claim- 1. In the art of reining iron directly from thesmelting-furnace, the process of equalizing the chemical composition ofthe crude metal by thoroughly commingling or mixing together theliquid-metal charge and subsequently refining the mixed and equalizedcharge, substantially as and for the purposes described.

2. In the art of mixing molten metal to secure uniformity of the same inits constituent parts preparatory to further treatment, the process ofintroducing into a mixing-receptacle successive portions of moltel metalununiform in their non-metallic constituents, (sulphur, silicon, &c.,)removing portions only of the compositel molten contents of thereceptacle Without entirely draining or emptying the same, andsuccessively replenishing the receptacle With fresh ununiform additions,substantially as and for the purposes described.

In testimony Whereof I have hereunto set my hand this 9th day of August,A. D. 1888.

VILLIAM R. JONES.

Witnesses E. J. SMAIL, W. BAKEWELL.

